a
a
x1
b
b
b
x1
b
x1
c
c
d
x1
c
x1
d
d
d
x1
b
c
x1
c
b
x1
b
c
d
x1
a
x1
2.2
b
x1
c
d
x1
a
a
x1
b
x1
b
c
x1
c
b
x1
a
a
x1
b
b
x1
b
c
d
x1
a
x1
b
x1
c
c
d
x1
b
c
x1
b
x1
a
a
x1
b
b
b
x1
true
a
a
x1
b
b
b
x1
b
c
x1
b
x1
b
c
d
x1
a
x1
a
a
x1
b
x1
a
a
x1
b
b
x1
true
a
1
1
22
d
1
1
2
b
1
1
14
c
1
1
6
c
1
0
a
1
1
7
b
1
1
0
b
c
x1
c
b
x1
a
a
x1
b
b
b
x1
c
x1
d
d
d
x1
b
c
d
x1
a
x1
b
x1
c
c
d
x1
b
x1
c
c
d
x1
false
b
c
x1
c
b
x1
false
b
x1
c
d
x1
false
NaTT
certifiable-1.6